+ /* If the function starts with a branch (to startup code at the end)
+ the last instruction should bring us back to the first
+ instruction of the real code. */
+ if (i386_follow_jump (start_pc) != start_pc)
+ pc = i386_follow_jump (pc);
+
+ return pc;
+}
+
+/* This function is 64-bit safe. */
+
+static CORE_ADDR
+i386_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
+{
+ gdb_byte buf[8];
+
+ frame_unwind_register (next_frame, PC_REGNUM, buf);
+ return extract_typed_address (buf, builtin_type_void_func_ptr);
+}
+\f
+
+/* Normal frames. */
+
+static struct i386_frame_cache *
+i386_frame_cache (struct frame_info *next_frame, void **this_cache)
+{
+ struct i386_frame_cache *cache;
+ gdb_byte buf[4];
+ int i;
+
+ if (*this_cache)
+ return *this_cache;
+
+ cache = i386_alloc_frame_cache ();
+ *this_cache = cache;
+
+ /* In principle, for normal frames, %ebp holds the frame pointer,
+ which holds the base address for the current stack frame.
+ However, for functions that don't need it, the frame pointer is
+ optional. For these "frameless" functions the frame pointer is
+ actually the frame pointer of the calling frame. Signal
+ trampolines are just a special case of a "frameless" function.
+ They (usually) share their frame pointer with the frame that was
+ in progress when the signal occurred. */
+
+ frame_unwind_register (next_frame, I386_EBP_REGNUM, buf);
+ cache->base = extract_unsigned_integer (buf, 4);
+ if (cache->base == 0)
+ return cache;
+
+ /* For normal frames, %eip is stored at 4(%ebp). */
+ cache->saved_regs[I386_EIP_REGNUM] = 4;
+
+ cache->pc = frame_func_unwind (next_frame, NORMAL_FRAME);
+ if (cache->pc != 0)
+ i386_analyze_prologue (cache->pc, frame_pc_unwind (next_frame), cache);
+
+ if (cache->stack_align)
+ {
+ /* Saved stack pointer has been saved in %ecx. */
+ frame_unwind_register (next_frame, I386_ECX_REGNUM, buf);
+ cache->saved_sp = extract_unsigned_integer(buf, 4);
+ }
+
+ if (cache->locals < 0)
+ {
+ /* We didn't find a valid frame, which means that CACHE->base
+ currently holds the frame pointer for our calling frame. If
+ we're at the start of a function, or somewhere half-way its
+ prologue, the function's frame probably hasn't been fully
+ setup yet. Try to reconstruct the base address for the stack
+ frame by looking at the stack pointer. For truly "frameless"
+ functions this might work too. */
+
+ if (cache->stack_align)
+ {
+ /* We're halfway aligning the stack. */
+ cache->base = ((cache->saved_sp - 4) & 0xfffffff0) - 4;
+ cache->saved_regs[I386_EIP_REGNUM] = cache->saved_sp - 4;
+
+ /* This will be added back below. */
+ cache->saved_regs[I386_EIP_REGNUM] -= cache->base;
+ }
+ else
+ {
+ frame_unwind_register (next_frame, I386_ESP_REGNUM, buf);
+ cache->base = extract_unsigned_integer (buf, 4) + cache->sp_offset;
+ }
+ }
+
+ /* Now that we have the base address for the stack frame we can
+ calculate the value of %esp in the calling frame. */
+ if (cache->saved_sp == 0)
+ cache->saved_sp = cache->base + 8;
+
+ /* Adjust all the saved registers such that they contain addresses
+ instead of offsets. */
+ for (i = 0; i < I386_NUM_SAVED_REGS; i++)
+ if (cache->saved_regs[i] != -1)
+ cache->saved_regs[i] += cache->base;
+
+ return cache;
+}
+
+static void
+i386_frame_this_id (struct frame_info *next_frame, void **this_cache,
+ struct frame_id *this_id)
+{
+ struct i386_frame_cache *cache = i386_frame_cache (next_frame, this_cache);
+
+ /* This marks the outermost frame. */
+ if (cache->base == 0)
+ return;
+
+ /* See the end of i386_push_dummy_call. */
+ (*this_id) = frame_id_build (cache->base + 8, cache->pc);
+}
+
+static void
+i386_frame_prev_register (struct frame_info *next_frame, void **this_cache,
+ int regnum, int *optimizedp,
+ enum lval_type *lvalp, CORE_ADDR *addrp,
+ int *realnump, gdb_byte *valuep)
+{
+ struct i386_frame_cache *cache = i386_frame_cache (next_frame, this_cache);
+
+ gdb_assert (regnum >= 0);
+
+ /* The System V ABI says that:
+
+ "The flags register contains the system flags, such as the
+ direction flag and the carry flag. The direction flag must be
+ set to the forward (that is, zero) direction before entry and
+ upon exit from a function. Other user flags have no specified
+ role in the standard calling sequence and are not preserved."
+
+ To guarantee the "upon exit" part of that statement we fake a
+ saved flags register that has its direction flag cleared.
+
+ Note that GCC doesn't seem to rely on the fact that the direction
+ flag is cleared after a function return; it always explicitly
+ clears the flag before operations where it matters.
+
+ FIXME: kettenis/20030316: I'm not quite sure whether this is the
+ right thing to do. The way we fake the flags register here makes
+ it impossible to change it. */
+
+ if (regnum == I386_EFLAGS_REGNUM)
+ {
+ *optimizedp = 0;
+ *lvalp = not_lval;
+ *addrp = 0;
+ *realnump = -1;
+ if (valuep)
+ {
+ ULONGEST val;
+
+ /* Clear the direction flag. */
+ val = frame_unwind_register_unsigned (next_frame,
+ I386_EFLAGS_REGNUM);
+ val &= ~(1 << 10);
+ store_unsigned_integer (valuep, 4, val);
+ }
+
+ return;
+ }
+
+ if (regnum == I386_EIP_REGNUM && cache->pc_in_eax)
+ {
+ *optimizedp = 0;
+ *lvalp = lval_register;
+ *addrp = 0;
+ *realnump = I386_EAX_REGNUM;
+ if (valuep)
+ frame_unwind_register (next_frame, (*realnump), valuep);
+ return;
+ }
+
+ if (regnum == I386_ESP_REGNUM && cache->saved_sp)
+ {
+ *optimizedp = 0;
+ *lvalp = not_lval;
+ *addrp = 0;
+ *realnump = -1;
+ if (valuep)
+ {
+ /* Store the value. */
+ store_unsigned_integer (valuep, 4, cache->saved_sp);
+ }
+ return;
+ }
+
+ if (regnum < I386_NUM_SAVED_REGS && cache->saved_regs[regnum] != -1)
+ {
+ *optimizedp = 0;
+ *lvalp = lval_memory;
+ *addrp = cache->saved_regs[regnum];
+ *realnump = -1;
+ if (valuep)
+ {
+ /* Read the value in from memory. */
+ read_memory (*addrp, valuep,
+ register_size (current_gdbarch, regnum));
+ }
+ return;
+ }
+
+ *optimizedp = 0;
+ *lvalp = lval_register;
+ *addrp = 0;
+ *realnump = regnum;
+ if (valuep)
+ frame_unwind_register (next_frame, (*realnump), valuep);
+}
+
+static const struct frame_unwind i386_frame_unwind =
+{
+ NORMAL_FRAME,
+ i386_frame_this_id,
+ i386_frame_prev_register
+};
+
+static const struct frame_unwind *
+i386_frame_sniffer (struct frame_info *next_frame)
+{
+ return &i386_frame_unwind;
+}
+\f
+
+/* Signal trampolines. */
+
+static struct i386_frame_cache *
+i386_sigtramp_frame_cache (struct frame_info *next_frame, void **this_cache)
+{
+ struct i386_frame_cache *cache;
+ struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
+ CORE_ADDR addr;
+ gdb_byte buf[4];
+
+ if (*this_cache)
+ return *this_cache;
+
+ cache = i386_alloc_frame_cache ();
+
+ frame_unwind_register (next_frame, I386_ESP_REGNUM, buf);
+ cache->base = extract_unsigned_integer (buf, 4) - 4;
+
+ addr = tdep->sigcontext_addr (next_frame);
+ if (tdep->sc_reg_offset)
+ {
+ int i;
+
+ gdb_assert (tdep->sc_num_regs <= I386_NUM_SAVED_REGS);
+
+ for (i = 0; i < tdep->sc_num_regs; i++)
+ if (tdep->sc_reg_offset[i] != -1)
+ cache->saved_regs[i] = addr + tdep->sc_reg_offset[i];
+ }
+ else
+ {
+ cache->saved_regs[I386_EIP_REGNUM] = addr + tdep->sc_pc_offset;
+ cache->saved_regs[I386_ESP_REGNUM] = addr + tdep->sc_sp_offset;
+ }